What are the symptoms of grape phylloxera?
An in-depth explanation for netizens about the symptoms of grape phylloxera in green plant and flower cultivation, with specific details as follows:
What are the symptoms of grape phylloxera?
Some grape growers report that they have found dense hair spots on the leaves of their grapes, which looks very much like a disease, and no treatment seems to work. In fact, this is grape phylloxera, which is a type of pest. However, due to its symptoms being very similar to a disease, it is commonly referred to as a disease. What are the symptoms of grape phylloxera? How can it be prevented?
Symptoms and impact of grape phylloxera
After grape phylloxera infection, initial symptoms include the appearance of light spots on the back of the leaves, with the leaf surface bulging and the back densely covered with felt-like hairs, initially white and later turning to tea-brown. The felt layer is formed by the hypertrophy of the grape leaf epidermal tissue under the stimulation of mites, causing the leaves to contract.
If the damage is more severe, the leaves will develop numerous dark brown spots and may scorch and fall off. The stems and rachis become brittle and are easily broken. The fruit surface becomes rusty, the skin rough, and sometimes cracks. This can weaken the tree and reduce yield.
Methods to control grape phylloxera
1. Clean the garden in winter
In winter, you can clean up the grape garden by pruning, removing dead branches, leaves, and weeds, deeply covering the orchard to destroy the overwintering sites of grape phylloxera, and spraying a mixture of potassium sulfate on the plants. In the early stages of grape growth, when damaged leaves are found, they should be removed immediately to prevent further spread.
2. Remove buds
Grape phylloxera mainly inhabits bud scales, so bud removal and pinching can also be used for control. The best time for bud removal is when the buds have grown to 1 centimeter. Early buds are too small and inconvenient to handle, wasting the nutrients of the grapevine after pruning. The removed buds need to be taken out of the grape garden and buried deep. The suckers at the base of the grapevine not only affect ventilation and light penetration but also serve as habitats for grape phylloxera, so they need to be cleared promptly. Additionally, the growth of new shoots is also a major site of damage by phylloxera. When fixing new shoots, the affected ones should be buried deep.
3. Chemical control
In spring, when grapes start to sprout and grow, phylloxera also becomes active. Therefore, once phylloxera is detected, a potassium sulfate mixture can be sprayed on the grapevines. However, the mixture may not kill all the phylloxera, so it is necessary to spray other chemicals multiple times during the peak activity period of phylloxera.
The above are the symptoms, impact, and control methods of grape phylloxera. If infected with grape phylloxera, comprehensive control is necessary. Currently, grape phylloxera is more common in the north and slightly less in the south. Farmers must pay attention to observation and timely control during grape cultivation to avoid yield reduction.
The above introduction to the symptoms of grape phylloxera is provided for netizens' reference.